The aircraft is an Avro Anson Mk1, serving with a Polish unit. It's a type much smaller than the Dakota.
The Anson was originally designed as a maritime patrol aircraft, entering service in the mid-1930s, but was already obsolete in that role by the outbreak of WW2, being mainly replaced by the Hudson.
It went on to serve in training units, for navigation and radio training, but also remained in maritime use in a secondary role. Off the top of my head, as a pure guess, it's possible that this particular aircraft was based at Millom or Carlisle, as Anson squadrons both operated from there, one squadron at least being Polish.
I have some better photos, but as a quick post, here is the Anson at Duxford.
The type, in later Marks, was still in service with the RAF in the late 1960s, having rightly earned the nickname 'Faithfull Annie'.
Hope this helps a bit.